In 3GPP (3rd Generation Partnership Project) which is a project aiming to standardize a mobile communication system, the standardization of an LTE Advanced, which is a sophisticated version of LTE (Long Term Evolution), is conducted after 3GPP Release 10.
The LTE and the LTE Advanced may employ frequency division duplex (FDD) or time division duplex (TDD).
Furthermore, the LTE and the LTE Advanced introduce a home base station that is a small base station provided to a home or a company (refer to Non-Patent Literature 1). To impose a connection restriction, the home base station may constitute a CSG (Closed Subscriber Group) cell connectable by a specific user only.
Moreover, the LTE Advanced introduces carrier aggregation, in which carriers (frequency bands) in the LTE are positioned as component carriers and a combination of a plurality of carriers is used for radio communication, in order to achieve a wider band while ensuring backward compatibility with the LTE (refer to Non-Patent Literature 1).